Torque screw

[high psi]

I'm not trying to argue.

But, From everything I've read about the so called 'Torque Screw' (which it's NOT) is that is has no effect above 1100 RPM or so. It's simply there for emissions. It was added for the 93 IDIT in order for the truck to pass the 'Snap Test'

The Turbo will not spool/boost enough to burn the added fuel at low RPM's. It's there to trim the lower RPM fuel, and still allow max delivery at higher RPM.

The theory You've described goes against everything I've read.

Go Here and read the OPTIONS list at the bottom of the page. http://www.stanadyne.com/view.php?id=40

"•Low Speed Fuel Limiter (smoke and emissions reduction) "

The biggest problem with these rigs is they won't build boost until 1500 RPM's+
So there's no sense in trying to inject more fuel before the boost comes up.

Here's a common situation with the IDIT. Loaded with a good load You come to a hill. Your starting to loose some speed, so You hit the throttle a little. As the truck slows, RPM's drop. Once You get to 1300-1400 RPM's the coal is rolling and EGT's are climbing. Then it's time to downshift. (You've gotta be able to BURN that fuel. If You keep pouring fuel down 'er, She just keeps getting hotter)
Now that You've down shifted, the EGT's are still up there (from the over fueling at low RPM) The EGT's will come down, once the engine can BURN all of the fuel.

My theory is: Why fight the elevated EGT's, by over fueling at low RPM's?

The page you referenced is the newer stuff. It's a torque screw. I know I'm kinda an unknown on here, but I know a little something about these pumps and they're still old technology. The amount of overfuel is minimal (talking like 1-2% if memory serves), it's just enough to kick the rpm's back up when there's a load applied to the engine. It's not some kind of massive overfuel, nor does it keep climbing as the rpm's keep dropping. once you've dropped the few hundred rpm it takes to hit the max fuel delivery it stops climbing and the rpm's keep dropping if the load is too much or increases more. I could see the torque screw helping with the snap test since with no load to pull the rpm's down, as in a snap test, the torque screw will cut the fuel back from the max setting. It's only when a load causes the rpm's to drop that it'll fuel up.

 

[f-two-fiddy]

There was a Stanadyne Tech article posted here a year or so ago. The Low RPM Fuel Limit was explained in it.

The pic is of a DB4, but the header clearly states DB2 & DB4.

 

[93cc7.3]

lots of good info but maybe i missed it has anyone told us where this screw is located

 

[dyoung14]

I'm not trying to argue.

But, From everything I've read about the so called 'Torque Screw' (which it's NOT) is that is has no effect above 1100 RPM or so. It's simply there for emissions. It was added for the 93 IDIT in order for the truck to pass the 'Snap Test'

The Turbo will not spool/boost enough to burn the added fuel at low RPM's. It's there to trim the lower RPM fuel, and still allow max delivery at higher RPM.

The theory You've described goes against everything I've read.

Go Here and read the OPTIONS list at the bottom of the page. http://www.stanadyne.com/view.php?id=40

"•Low Speed Fuel Limiter (smoke and emissions reduction) "

The biggest problem with these rigs is they won't build boost until 1500 RPM's+
So there's no sense in trying to inject more fuel before the boost comes up.

Here's a common situation with the IDIT. Loaded with a good load You come to a hill. Your starting to loose some speed, so You hit the throttle a little. As the truck slows, RPM's drop. Once You get to 1300-1400 RPM's the coal is rolling and EGT's are climbing. Then it's time to downshift. (You've gotta be able to BURN that fuel. If You keep pouring fuel down 'er, She just keeps getting hotter)
Now that You've down shifted, the EGT's are still up there (from the over fueling at low RPM) The EGT's will come down, once the engine can BURN all of the fuel.

My theory is: Why fight the elevated EGT's, by over fueling at low RPM's?

you let yours get down below 2000 while pulling a big hill? i always keep mine around or above 2000 rpm while pulling a load

 

[Goofyexponent]

lots of good info but maybe i missed it has anyone told us where this screw is located

It's driver side of the pump, on the back above the housing. Just above where all the lines hook to the pump. It's on a 45 degree angle to the valley pan.

It is a set screw with a jam nut. stick an allen wrench in and back the screw out, thread the jam nut down and tighten the screw and nut up.

BE CAREFUL!!! IT DELIVERS FUEL FAST AND HARD WITH MINIMAL ADJUSTMENT!!!!!

Why do I get the feeling me and Sycostang67 started up a whole new ball game with this torque screw experimentation?

 

[93cc7.3]

because you just did lol im just getting into this whole diesel thing so im looking to experiment im budgeting now to have the money to compound turbo and remote mount and intercool but next year

 

[Goofyexponent]

Just be careful how much fuel you put into this motor. any type of tailpipe smoke generally means you are close to exceeding the maximum exhaust gas temperature (EGT) for our motors, whish is 1100 degrees F.

Lots of fuel in a cylinder can wash off protective oil and wear out rings, linings, crack pistons, burn valve seals, and do a LOT of damage to your wallet! lol

 

[matt-jenkins]

So, long story short in a dumbed down version this "Torque screw" does nothing more then increase EGT's at a low RPM?

 

[franklin2]

Why do I get the feeling me and Sycostang67 started up a whole new ball game with this torque screw experimentation?

You did, because I want to know how the pump works. I have seen brief explanations. I wonder what the training is like on becoming a certified rebuilder? It seems like this area of expertise is all tied up and with lots of stuff hush hush about it. I sure would like to get hold of a Stanadyne training manual on these things. I assume one exists, or do all the guys have to turn them back in or burn them after they go to the Stanadyne school

After saying all that, I wonder if you could even get parts if you did know what you were doing?

 

[FX4 Level2]

Awesome thread!

 

[Black dawg]

the "torque screw" limits max travel of the metering valve. take the lid off of the pump and look, its very simple. just back it out till it doesnt block the metering valve.

 

[f-two-fiddy]

Yes, but it only limits the metering valve until the RPM's reach a certain point.

 

[Black dawg]

it limits the metering valve till the gov starts pulling it away from the screw.

 

[matt-jenkins]

Well, I cranked mine out a fair bit this morning. didnt make a difference around town except more smoke when I walk on it. Tonight going down the highway my truck had way more get up and go at 130-140kph compared to how it used to be.

 

[Sycostang67]

I will probably wait until I have new injectors and the timing set before I mess with mine. I do believe I found it though. The screw on my pump sticks out at a 90* angle just above the round part that all the lines come from and has a anit-tamper cap on it. I think thats it anyhow.